Appendix D: Glossary of Bulk Carrier and Shipping Terminology

The maritime industry, and the bulk carrier sector in particular, uses a specialized vocabulary rich with technical, commercial, legal, and operational terms. A clear understanding of this terminology is essential for effective communication, accurate interpretation of documents, and safe operations. This glossary provides definitions for many of the key terms used throughout this guide and encountered in the daily life of a mariner or shore-based professional in the bulk shipping industry. A small sample is provided below.

Accommodation Ladder: A portable ladder or stairway, typically made of aluminum or steel, rigged on the ship’s side for personnel to embark and disembark when alongside a quay.
Ad Valorem Freight: Freight calculated based on the value of the cargo, rather than its weight or volume. Rare for bulk cargoes.
Agency Fee: A fee paid by the shipowner or charterer to the ship’s agent for services rendered in port.
Agent (Ship’s Agent / Port Agent): A person or firm appointed to represent the interests of a shipowner or charterer in a port, handling all essential local arrangements such as customs clearance, pilotage, tugs, provisions, crew changes, and communication with local authorities.
Air Draft: The vertical distance from the water line to the highest point of the vessel, typically the top of a mast or antenna. Critical for passing under bridges, loading arms, or other overhead obstructions.
ALARP (As Low As Reasonably Practicable): A principle in risk management stating that risks should be reduced to a level that is as low as is reasonably practicable, balancing the cost and effort of further reduction against the risk level.
Alternate Hold Loading: A method of loading very dense cargoes (like iron ore) into non-adjacent holds (e.g., holds 1, 3, 5, 7) while leaving the intermediate holds (e.g., 2, 4, 6) empty or in ballast, in order to manage and reduce overall hull stresses. This must be done in accordance with the ship’s approved Loading Manual.
Angle of Repose: The steepest angle, measured from the horizontal, at which a piled, non-cohesive granular material (like grain or some ores) will remain stable without sliding or slumping. It is a critical factor in assessing a cargo’s propensity to shift.
Annual Survey: A yearly inspection by a Classification Society surveyor to verify that a vessel is being maintained in a condition that complies with Class rules and that statutory equipment remains satisfactory.
Anti-Fouling System (AFS): A specialized coating applied to the ship’s underwater hull to prevent or slow the growth of marine organisms such as barnacles and algae, which increase hull resistance and fuel consumption.
Appraisal (Passage Planning): The first stage of voyage planning, involving the comprehensive gathering and assessment of all information relevant to the intended voyage.
ARPA (Automatic Radar Plotting Aid): An advanced function of a ship’s radar system that automatically acquires, tracks, and plots targets to provide information on their course, speed, Closest Point of Approach (CPA), and Time to Closest Point of Approach (TCPA), serving as a vital tool for collision avoidance.
Arrived Ship: A legal term in charter parties signifying that a vessel has reached the contractually agreed destination (port or berth) and is at the immediate and effective disposition of the charterer. The valid tendering of the Notice of Readiness (NOR) often depends on this condition being met.
Aft Peak Tank (APT): A ballast tank located at the extreme stern of the vessel, aft of the last cargo hold or engine room.
AIS (Automatic Identification System): A VHF radio-based transponder system that automatically transmits and receives vessel identification, position, course, speed, and other data to and from other ships and shore stations, enhancing situational awareness and collision avoidance.

Bale Capacity: The internal volume of a cargo hold available for stowing non-free-flowing cargo (e.g., packaged goods, bales), measured between the inside of frames or cargo battens and from the tank top to the underside of deck beams. It is always less than Grain Capacity.
Ballast Water Management Convention (BWMC): The IMO convention establishing global regulations for the control and management of ships’ ballast water and sediments to prevent the spread of Harmful Aquatic Organisms and Pathogens (HAOP).
Ballast Water Management Plan (BWMP): A ship-specific plan, approved by the Administration, detailing the procedures for managing ballast water and sediments in accordance with the BWM Convention.
Ballast Water Management System (BWMS / BWTS): Onboard equipment designed to treat ballast water to remove, kill, or render harmless HAOP in order to meet the D-2 performance standard of the BWM Convention.
Ballast Water Record Book (BWRB): An official logbook for recording all ballast water operations (uptake, exchange, treatment, discharge, sediment disposal) as required by the BWM Convention.
BCSN (Bulk Cargo Shipping Name): The official name for a solid bulk cargo as listed in the IMSBC Code.
Beam: The maximum width (breadth) of a vessel.
Bending Moment (BM): A measure of the bending forces acting on a ship’s hull along its length, resulting from the uneven distribution of weight and buoyancy. Excessive bending moments can cause the ship to hog or sag beyond its structural limits.
Berth: A specific place alongside a quay, jetty, or pier where a vessel is moored for loading or discharging.
Bill of Lading (B/L): A key commercial document that serves three main functions: it is a receipt for the cargo shipped, evidence of the contract of carriage, and a document of title to the goods.
BIMCO (Baltic and International Maritime Council): A large international shipping association that creates standard contracts of carriage (charter parties), clauses, and provides information and advice to the industry.
Bitts (Mooring Bitts): Strong, paired vertical posts on a ship’s deck used for making mooring lines fast.
Block Coefficient (Cb): A ratio representing the “fullness” of a ship’s underwater hull shape. Cb = Volume of Displacement / (Length x Beam x Draft). Bulk carriers have a high (full) block coefficient, typically > 0.8.
Bosun (Boatswain): The senior-most rating in the deck department, responsible for supervising other deck ratings in tasks such as mooring, anchoring, cargo gear operation, and deck maintenance.
Bridge Resource Management (BRM): The effective management and utilization of all available resources—human (bridge team, pilot), equipment (navigational aids), and information—to achieve safe and efficient navigation and vessel operation.
Bulwark: The solid steel plating extension above the main deck along the ship’s sides, serving as a safety barrier.

Capesize: A class of very large bulk carriers, typically over 150,000 DWT, so named because their size prevents them from transiting the Panama or Suez canals, requiring them to travel around the Cape of Good Hope or Cape Horn.
Cargo Sweat: Condensation that forms directly on the surface of a cold cargo when warm, moist air is introduced into the hold.
CATZOC (Category of Zone of Confidence): A system used in Electronic Navigational Charts (ENCs) to indicate the accuracy and quality of the hydrographic data (e.g., depth soundings, position of features) in a specific geographical area.
Certificate of Classification: A document issued by a Classification Society confirming that a vessel, as of its last survey, complies with the society’s technical rules for construction and maintenance.
Charter Party (C/P): A legal contract between a shipowner and a charterer for the hire of a vessel. Common types include Voyage Charter, Time Charter, and Bareboat Charter.
Chief Officer (C/O or Chief Mate): The head of the deck department, second in command to the Master, and typically responsible for cargo operations, stability, deck maintenance, and safety equipment.
CII (Carbon Intensity Indicator): An IMO regulation under MARPOL Annex VI that measures a ship’s operational carbon efficiency. Ships of 5,000 GT and above are rated annually from A (best) to E (worst).
Classification Society: A non-governmental organization that establishes and maintains technical standards for the construction and maintenance of ships (e.g., Lloyd’s Register, ABS, DNV). They survey ships to ensure compliance with these “Class Rules.”
COLREGs (International Regulations for Preventing Collisions at Sea, 1972): The international “rules of the road” for maritime traffic.
Condition of Class (CoC): A deficiency or requirement issued by a Classification Society surveyor that must be rectified by a specific deadline in order for the vessel to maintain its classification.
Constant (Ship’s Constant): The difference between a vessel’s observed lightship displacement (as determined by a draft survey) and its official lightship weight. It represents the weight of items not included in the lightship figure, such as accumulated stores, spares, sludge, paint, and minor structural modifications.
CPA (Closest Point of Approach): The minimum distance at which two vessels on their current courses and speeds will pass each other, as calculated by ARPA or other plotting methods.
CSU (Continuous Ship Unloader): A type of large, specialized shore-based equipment used for discharging bulk cargoes efficiently and with less dust than grabs.

Damage Stability: A vessel’s ability to remain afloat and stable after sustaining hull damage and flooding of one or more compartments.
Davit: A crane-like device on a ship’s deck used for lowering and hoisting lifeboats or rescue boats.
Deck Log Book: A chronological record of all events related to the navigation of the vessel and activities on deck.
Declaration of Security (DoS): A formal agreement between a ship and a port facility (or another ship) under the ISPS Code, outlining the security measures each will undertake during their interface.
Demurrage: A form of liquidated damages paid by a charterer to a shipowner for detaining the vessel in port beyond the laytime allowed for cargo operations.
Despatch (or Dispatch): A bonus paid by a shipowner to a charterer if cargo operations are completed before the allowed laytime has expired. Typically, the despatch rate is half the demurrage rate.
Designated Person Ashore (DPA): A key role under the ISM Code. The DPA is a shore-based person who has direct access to the highest level of management and is responsible for monitoring the safety and pollution prevention aspects of the company’s fleet.
Dew Point: The temperature at which air becomes saturated with water vapor (100% Relative Humidity) and condensation (sweat) begins to form. It is the most important parameter for making ventilation decisions.
DGPS (Differential Global Positioning System): An enhancement to GPS that uses a network of fixed ground-based reference stations to broadcast corrections, providing greater position accuracy than standard GPS.
Document of Authorization (for Grain): A certificate issued by the Flag State confirming that a vessel is capable of complying with the stability requirements of the International Grain Code.
Document of Compliance (DOC): A certificate issued to a shipping company confirming that its Safety Management System (SMS) complies with the requirements of the ISM Code.
DPA: See Designated Person Ashore.
Draft (or Draught): The vertical distance from the waterline to the lowest point of the ship’s hull (the keel).
Draft Survey: A method of determining the weight of cargo loaded or discharged by measuring the change in the ship’s displacement.
DRI (Direct Reduced Iron): A high-quality metallic iron product produced from iron ore without melting it. Certain forms (e.g., HBI – Hot Briquetted Iron) are common bulk cargoes, but some are highly reactive (Group B), prone to self-heating and hydrogen emission when wet.
DWT (Deadweight Tonnage): The total carrying capacity of a vessel, measured in tonnes, including cargo, fuel, water, ballast, stores, crew, and passengers. It is the difference between the laden displacement and the lightship weight.

ECDIS (Electronic Chart Display and Information System): A computer-based navigation system that complies with IMO standards and can be used as an alternative to paper nautical charts. It integrates ENC data with position information from GPS and other sensors.
EEDI (Energy Efficiency Design Index): An IMO regulation for new ships, setting a minimum energy efficiency level based on a formula for CO₂ emissions per transport work.
EEXI (Energy Efficiency Existing Ship Index): An IMO regulation requiring existing ships to meet a certain technical energy efficiency standard, often necessitating modifications like Engine Power Limitation (EPL).
EmS (Emergency Response Procedures for Ships Carrying Dangerous Goods): Found in a supplement to the IMDG Code, providing guidance on emergency response actions for fire (F-schedules) and spillage (S-schedules) involving specific dangerous goods.
ENC (Electronic Navigational Chart): The official vector chart database, produced by a national hydrographic office, for use in an ECDIS.
Enhanced Survey Programme (ESP): A mandatory, rigorous survey regime under SOLAS for bulk carriers and oil tankers, requiring more detailed inspections, close-up surveys, and thickness measurements of hull structures to address concerns about structural integrity and ageing.
EPIRB (Emergency Position Indicating Radio Beacon): A GMDSS distress beacon which, when activated, transmits a signal via satellite to SAR authorities, providing the vessel’s identity and position.
ETA / ETB / ETC / ETS: Estimated Time of Arrival / Berthing / Completion / Sailing.

Fairlead: A fitting on deck or in the bulwark used to guide mooring lines or ropes, preventing them from chafing.
Fenders: Cushions (rubber, pneumatic, etc.) placed between the ship and the quay (or another ship) to absorb impact during berthing and prevent damage.
FFA (Fire-Fighting Appliances): The collective term for all fire-fighting equipment onboard, including pumps, hydrants, hoses, extinguishers, fixed systems, and fireman’s outfits.
FIOS (Free In and Out, Stowed): A charter party term meaning that the charterer is responsible for the cost of loading, stowing, and discharging the cargo.
Flag State: The nation in which a vessel is registered and whose laws it is subject to. The Flag State has the primary responsibility for ensuring the vessel complies with international conventions.
Flow Moisture Point (FMP): The percentage moisture content at which a granular cargo (Group A) will begin to behave like a liquid when subjected to vibration or impact. The TML is calculated from the FMP.
Fore Peak Tank (FPT): A ballast tank located at the extreme bow of the vessel, forward of the collision bulkhead.
Free Pratique: Permission granted by port health authorities allowing the ship to interact with the shore, signifying it is free from contagious diseases.
Free Surface Effect: The reduction in a vessel’s metacentric height (GM) caused by the movement of liquid in slack (partially filled) tanks as the ship heels. This reduces stability.
Freeboard: The vertical distance from the waterline to the main deck.
Fumigation: The process of treating a cargo or space with gaseous pesticides (fumigants) to kill pests.

Gangway: The portable bridge used for personnel to walk between the ship and the shore.
Garbage Management Plan: A mandatory plan under MARPOL Annex V detailing procedures for collecting, storing, processing, and disposing of all types of garbage generated onboard.
Garbage Record Book (GRB): A mandatory logbook for recording all disposal and discharge of garbage.
Geared Vessel: A ship equipped with its own cranes or derricks for handling cargo.
Gearless Vessel: A ship without its own cargo handling equipment, relying entirely on shore-based cranes.
GM (Metacentric Height): The vertical distance between the ship’s center of gravity (G) and its transverse metacentre (M). It is a primary indicator of initial transverse stability.
GMDSS (Global Maritime Distress and Safety System): An internationally agreed set of safety procedures, equipment, and communication protocols for increasing safety and making it easier to rescue ships in distress.
GNSS (Global Navigation Satellite System): The generic term for satellite navigation systems that provide autonomous geo-spatial positioning, such as GPS (USA), GLONASS (Russia), Galileo (EU), and BeiDou (China).
Grain Capacity: The total internal volume of a cargo hold, including all recesses, available for free-flowing “grain-like” cargo.
Grain Clean: A very high standard of hold cleanliness required for the carriage of grain, meaning the hold is completely clean, dry, and free of previous cargo residues, insects, and odors.
GZ Curve (Curve of Statical Stability): A graph that plots the righting lever arm (GZ) against angles of heel for a specific loading condition, providing a comprehensive picture of a vessel’s transverse stability at all angles.

Handysize / Handymax: Classes of smaller to medium-sized bulk carriers (typically ranging from ~20,000 to ~60,000 DWT), known for their operational flexibility and often being geared.
Hatch Coaming: The raised steel structure surrounding a hatch opening on the deck, to which the hatch cover seals and secures.
Hawsepipe: The heavy steel pipe in the bow through which the anchor chain passes.
Hogging: A condition where a ship’s hull bends upwards in the middle due to weight distribution or wave action, causing the deck to be in tension and the bottom in compression.
Hopper Tanks: Ballast tanks with sloping sides in the lower part of a cargo hold, designed to facilitate cargo flow towards the center during discharge and to carry ballast.
Hospital Clean: The highest possible standard of hold cleanliness, requiring the removal of all traces of previous cargo, rust scale, and dirt, often verified by a “white glove” test. Required for very sensitive cargoes like kaolin.
HME (Harmful to the Marine Environment): A classification under MARPOL Annex V for cargo residues that are harmful to the sea. The discharge of HME residues into the sea is prohibited.
HRU (Hydrostatic Release Unit): A device fitted to liferafts that automatically releases the raft from its cradle and allows it to float free and inflate if the ship sinks to a certain depth.
Hygroscopic: The property of a substance to attract and hold water molecules from the surrounding environment (air). Many bulk cargoes, such as grains, sugar, salt, and some fertilizers, are hygroscopic.

IACS (International Association of Classification Societies): An organization of the world’s leading classification societies that establishes common technical standards (Common Structural Rules – CSR) and works to promote maritime safety and environmental protection.
IGC (International Grain Code): The mandatory IMO code that sets out specific stability and stowage requirements for ships carrying grain in bulk.
IMDG Code (International Maritime Dangerous Goods Code): The mandatory IMO code governing the safe transport of dangerous goods in packaged form.
IMO (International Maritime Organization): The United Nations’ specialized agency with responsibility for the safety and security of shipping and the prevention of marine pollution by ships.
IMSBC Code (International Maritime Solid Bulk Cargoes Code): The mandatory IMO code governing the safe stowage and carriage of solid bulk cargoes.
In-Water Survey (IWS): An inspection of the underwater part of a ship’s hull conducted by divers with CCTV equipment, which under certain conditions may be accepted by a Classification Society in lieu of one of the two dry-docking surveys required in a five-year period.
INTERCARGO (The International Association of Dry Cargo Shipowners): An industry association representing the interests of owners, operators, and managers in the dry bulk shipping sector.
Intermediate Survey: A survey conducted between the second and third annual surveys in a five-year cycle, more detailed than an annual survey and forming part of the requirements for maintaining Class and statutory certificates.
ISF (International Shipping Federation): Now part of the International Chamber of Shipping (ICS), an industry body representing shipowners.
ISM Code (International Safety Management Code): The mandatory IMO code for the safe management and operation of ships and for pollution prevention, requiring companies and their ships to establish and maintain a Safety Management System (SMS).
ISPS Code (International Ship and Port Facility Security Code): A mandatory IMO code comprising a set of measures to enhance the security of ships and port facilities against acts of terrorism and other unlawful acts.

JSA (Job Safety Analysis) / TRA (Task Risk Assessment): A systematic process of breaking down a job or task into steps, identifying the hazards associated with each step, and implementing control measures to mitigate the risks.

Keel: The primary structural member running along the centerline of the bottom of a ship.
KG: The vertical height of a ship’s center of gravity (G) above its keel (K).
KM: The vertical height of a ship’s transverse metacentre (M) above its keel (K).
KN Values (Cross Curves of Stability): A set of curves provided in a ship’s stability data from which the righting lever (GZ) can be calculated for any condition of loading and heel angle. GZ = KN - KG sin(θ).

Laden/Loaded Condition: The condition of a vessel when it is loaded with cargo.
Lay/Can (Laydays/Cancelling Date): A period specified in a voyage charter party. “Laydays” is the period during which the ship must present itself at the load port to be ready to load. “Cancelling Date” is the final date by which the ship must be ready; if she is not ready by this date, the charterer has the option to cancel the contract.
Laytime: The amount of time allowed in a voyage charter party for the loading and discharging of cargo.
LCB (Longitudinal Centre of Buoyancy): The longitudinal position of the geometric centre of the ship’s underwater volume.
LCF (Longitudinal Centre of Flotation): The longitudinal position of the geometric centre of the ship’s waterplane area. It is the point about which the ship trims.
LCG (Longitudinal Centre of Gravity): The longitudinal position of the ship’s center of gravity.
LFL (Lower Flammable Limit) / LEL (Lower Explosive Limit): The minimum concentration of a flammable gas or vapor in air below which it will not ignite.
Lightship Condition: The condition of a vessel complete in all respects but without any cargo, crew, stores, fuel, water, or ballast. Its weight is the “lightship weight.”
Liquefaction: The phenomenon where a solid granular cargo (Group A) with moisture content exceeding its TML behaves like a liquid due to compaction and vibration, leading to a rapid loss of ship stability.
List: A vessel’s transverse inclination from the vertical, caused by an uneven distribution of weight on either side of the centerline.
LLC (International Convention on Load Lines): The IMO convention that establishes rules for determining the minimum freeboard for ships, ensuring adequate reserve buoyancy.
Loadicator: See Loading Instrument.
Loading Computer/Instrument: An approved electronic software system onboard used to calculate and assess the vessel’s stability, trim, and longitudinal stresses for any given loading condition.
Loading Manual: A Class-approved manual specific to the vessel, containing detailed information on permissible stress limits, approved loading conditions (including alternate loading), tank capacities, and other data necessary for safe loading.
LOI (Letter of Indemnity): A document issued by one party (e.g., a charterer) to another (e.g., a shipowner/Master) to indemnify them against the consequences of complying with a request, such as delivering cargo without presentation of original Bills of Lading. Must be handled with extreme caution and usually requires owner’s and P&I Club approval.
LOP (Letter of Protest): A formal written statement issued by the Master to another party to record disagreement with an action, inaction, or condition, and to reserve the shipowner’s rights to claim for any resulting losses or damages.
LSA (Life-Saving Appliances): The collective term for all life-saving equipment onboard, including lifeboats, liferafts, lifejackets, immersion suits, lifebuoys, and pyrotechnics.
Luffing: The action of raising or lowering the jib (boom) of a crane to change its outreach (radius).

MARPOL (International Convention for the Prevention of Pollution from Ships): The main IMO convention covering the prevention of marine pollution by ships, divided into six Annexes.
Master Mariner: The official qualification and title of a person licensed to command a merchant vessel of any size, on any waters. The captain of the ship.
MHB (Materials Hazardous only in Bulk): A classification within the IMSBC Code for cargoes that possess chemical hazards when transported in bulk quantities but may not be classified as dangerous goods when in packaged form (some are also IMDG-classified). These are Group B cargoes.
MLC, 2006 (Maritime Labour Convention, 2006): An international convention establishing minimum working and living standards for seafarers. Often referred to as the “seafarers’ bill of rights.”
MMSI (Maritime Mobile Service Identity): A unique nine-digit number assigned to a ship’s radio station, used for identification in GMDSS and AIS systems.
Moor: To secure a vessel alongside a berth, pier, or another vessel using ropes or wires.
MTC (Moment to Change Trim by One Centimetre): The moment (in tonne-metres) required to change the ship’s total trim by one centimetre. Found in hydrostatic tables.

NAVTEX (Navigational Telex): An automated radio broadcast system for disseminating maritime safety information (MSI), including navigational warnings, meteorological forecasts, and SAR messages, to ships in coastal areas.
N.O.S. (Not Otherwise Specified): A term used in cargo codes (e.g., IMSBC Code) for cargoes that are not specifically listed by name. They require special assessment and agreement for carriage.
NOR (Notice of Readiness): A formal written notice given by the Master to the charterers or their agents, stating that the vessel has arrived and is ready in all respects to load or discharge cargo. The valid tender of NOR usually triggers the start of laytime.

OBO (Ore/Bulk/Oil Carrier): A type of combination carrier designed to carry either dry bulk cargoes or liquid oil cargoes in the same holds/tanks.
OCIMF (Oil Companies International Marine Forum): An industry association of oil companies that produces widely recognized best practice guidelines, particularly for tankers but many principles (e.g., mooring) are influential across shipping.
OOW (Officer of the Watch): The certified deck officer responsible for navigating the vessel and maintaining a safe watch on the bridge during their designated period (watch).
OWS (Oily Water Separator) / OFE (Oil Filtering Equipment): Mandatory equipment under MARPOL Annex I, used to separate oil from machinery space bilge water to ensure the effluent discharged to sea has an oil content not exceeding 15 ppm.

P&I Club (Protection and Indemnity Club): A mutual insurance association that provides liability insurance cover for shipowners against third-party claims, such as cargo damage, pollution, personal injury, and collision liability. They are also a major source of loss prevention advice.
Panamax: A class of bulk carriers whose dimensions (beam, length) were originally the maximum capable of transiting the original locks of the Panama Canal (typically ~60,000-80,000 DWT). “Neopanamax” or “New Panamax” refers to larger vessels that can fit through the expanded locks.
Parallel Indexing (PI): A navigational technique using radar to continuously monitor a vessel’s lateral position relative to a pre-planned track by maintaining a constant range from a radar-conspicuous object.
Permit to Work (PTW): A formal, documented safety system used to control high-risk, non-routine tasks such as hot work or enclosed space entry, ensuring that all hazards are assessed and all precautions are taken before, during, and after the work.
Pilot: A licensed mariner with expert knowledge of a local port or waterway who boards a vessel to advise the Master on its safe navigation and handling during transit, berthing, and unberthing.
Plimsoll Mark (Load Line Mark): A mark painted on the side of a ship’s hull indicating the maximum draft to which the vessel can be safely loaded in different water densities and seasons, as required by the Load Line Convention.
PMS (Planned Maintenance System): A systematic approach to organizing, scheduling, and documenting all maintenance activities onboard a vessel, shifting maintenance from a reactive to a proactive basis.
Port State Control (PSC): The inspection of foreign-flagged ships in national ports to verify their compliance with international safety, security, and environmental conventions.
PPE (Personal Protective Equipment): Equipment worn by individuals to minimize exposure to hazards, such as hard hats, safety shoes, gloves, goggles, respirators, harnesses, and immersion suits.
Psychrometer (Sling Psychrometer): An instrument containing both a dry-bulb and a wet-bulb thermometer, used to measure the dry bulb temperature and wet bulb temperature of the air, from which relative humidity and dew point can be determined.

Quarter Mean Draft (or Mean of Means Draft): The mean of the forward, aft, and (multiple) midship drafts, calculated using a specific formula (e.g., Simpson’s Rules) to provide the most accurate mean draft for entering hydrostatic tables, as it accounts for the effects of hog or sag.

RACON (Radar Beacon): A transponder fitted to a navigational aid (like a buoy or lighthouse) which, when triggered by a ship’s radar signal, transmits a characteristic signal back that appears on the ship’s radar screen, providing positive identification and range.
Reserve Buoyancy: The volume of the enclosed, watertight part of a ship above the waterline. It is a measure of the ship’s ability to remain afloat after taking on additional weight (e.g., from flooding). Freeboard is a direct indicator of reserve buoyancy.
Righting Arm/Lever (GZ): The perpendicular distance between the vertical lines of action of the forces of gravity (acting downwards through G) and buoyancy (acting upwards through B) when a ship is heeled. The magnitude of GZ determines the vessel’s ability to return to an upright position.
RightShip: A prominent maritime risk management and vetting organization, widely used in the dry bulk sector to assess the safety and environmental performance of vessels on behalf of charterers.
ROB (Remaining on Board): Cargo that remains in the holds after discharge is completed.
RO (Recognized Organization): An organization, typically a Classification Society, that is authorized by a Flag State Administration to perform statutory survey and certification work on its behalf.

Sagging: A condition where a ship’s hull bends downwards in the middle due to weight distribution or wave action, causing the deck to be in compression and the bottom in tension.
SART (Search and Rescue Transponder): A portable radar transponder which, when activated in a distress situation, appears as a series of distinctive dots on the radar screens of nearby vessels and aircraft, aiding in location. An AIS-SART performs a similar function using AIS signals.
SCBA (Self-Contained Breathing Apparatus): Equipment providing breathable air from its own supply (e.g., compressed air cylinders), worn to protect the user from oxygen-deficient, toxic, or smoke-filled atmospheres. Essential for fire-fighting and enclosed space rescue.
Scrubber (Exhaust Gas Cleaning System – EGCS): Equipment installed on a ship to remove sulphur oxides (SOx) from engine exhaust gases, allowing the vessel to continue using higher sulphur fuel oil while still complying with MARPOL Annex VI emission limits.
SEEMP (Ship Energy Efficiency Management Plan): A mandatory plan under MARPOL Annex VI for ships to monitor and improve their energy efficiency. It now includes parts related to IMO DCS (Data Collection System) and CII (Carbon Intensity Indicator).
Segregation: The planned separation of cargoes that are incompatible with each other due to the risks of dangerous chemical reactions, heat generation, or contamination.
Shearing Force (SF): The net vertical force at a transverse section of the hull, representing the tendency for one part of the ship to slide vertically relative to the adjacent part due to uneven loading.
Ship’s Sweat (Hull Sweat): Condensation that forms on the internal surfaces of a cargo hold (deckhead, shell plating) when the ship’s structure becomes colder than the dew point of the air inside the hold.
Slamming: The heavy impact of the ship’s bow or forward bottom area with the sea surface during heavy pitching, capable of causing significant structural damage.
Slop Tank: A tank designated for collecting oily water mixtures, such as drainage from cargo spaces on tankers or other oily residues, before processing or disposal.
SMS (Safety Management System): A structured and documented system required by the ISM Code, established by a shipping company to ensure safe ship operations and pollution prevention.
SOF (Statement of Facts): A chronological document detailing all events during a ship’s port call, jointly signed by ship and shore representatives, which forms the basis for laytime calculations.
SOLAS (International Convention for the Safety of Life at Sea): The most important international treaty concerning the safety of merchant ships, setting minimum standards for construction, equipment, and operation.
SOPEP (Shipboard Oil Pollution Emergency Plan): A mandatory plan providing procedures for responding to an oil pollution incident. For ships carrying noxious liquid substances, this may be an SMPEP (Shipboard Marine Pollution Emergency Plan).
Sounding: The process of measuring the depth of liquid in a tank, or the depth of water under a ship.
Special Survey: The most comprehensive survey of a ship’s hull and machinery conducted by a Classification Society every five years to renew the vessel’s Class certificate.
Specific Gravity / Relative Density: The ratio of the density of a substance to the density of a reference substance (usually water). In shipping, density (e.g., t/m³) is more commonly used.
Squat: The hydrodynamic phenomenon where a ship moving through shallow water sinks bodily deeper and may also change its trim. The effect increases significantly with speed.
SSAS (Ship Security Alert System): A discreet, covert system required by the ISPS Code, which allows a ship to transmit a security alert to a competent authority ashore without being obvious to anyone on the bridge or on the ship.
SSD (Self-Sustaining Decomposition): A hazardous property of some Ammonium Nitrate Based Fertilizers (ANBFs), where an exothermic decomposition, once initiated by heat, can propagate through the cargo mass even without an external air supply, producing large volumes of toxic gas.
Stevedore: A person or company contracted to load and discharge cargo from ships in port.
STCW (International Convention on Standards of Training, Certification and Watchkeeping for Seafarers): The IMO convention setting qualification standards for masters, officers, and watch personnel on seagoing merchant ships.
Stiff Ship: A vessel with a large GM (metacentric height), characterized by a short, fast, and often uncomfortable rolling period.
Stowage Factor (SF): The volume occupied by one unit of weight of a cargo, typically expressed as cubic metres per tonne (m³/t). A low stowage factor indicates a dense cargo; a high stowage factor indicates a light, voluminous cargo.
Strum Box (Rose Box): A strainer fitted over a suction inlet in a bilge or ballast tank to prevent debris from entering and choking the pipeline or pump.
Supramax: A class of bulk carrier larger than Handymax, typically around 50,000 to 60,000 DWT.

Tank Top: The plating that forms the floor of the cargo holds and the top of the double bottom tanks beneath them.
TCG (Transverse Centre of Gravity): The transverse (port/starboard) position of a ship’s center of gravity.
TCPA (Time to Closest Point of Approach): The time remaining until two vessels on their current courses and speeds will reach their CPA, as calculated by ARPA.
Tender Ship: A vessel with a small positive GM (metacentric height), characterized by a long, slow, and easy rolling period. While comfortable, a very tender ship has small stability reserves.
TML (Transportable Moisture Limit): A critical parameter for Group A cargoes. It is the maximum moisture content considered safe for carriage in a conventional ship. If the cargo’s actual moisture content exceeds the TML, it is liable to liquefy.
Toolbox Talk (TBT): An informal, short safety briefing conducted at the worksite immediately before a specific task begins, focusing on the immediate hazards and precautions.
Topside Wing Tanks: Ballast tanks located in the upper corners of a cargo hold, under the main deck and outboard of the hatch coamings. They contribute to ballast capacity, stability control, and self-trimming of cargo.
TPC (Tonnes Per Centimetre Immersion): The weight in tonnes that must be loaded or discharged to change the ship’s mean draft by one centimetre.
Trimming: The process of leveling a bulk cargo within a hold to minimize the risk of shifting and to optimize stowage.
Trim: The difference between the draft at the stern and the draft at the bow. Trim by the stern (aft draft > forward draft) is positive; trim by the head (forward draft > aft draft) is negative.
TSS (Traffic Separation Scheme): IMO-adopted sea lanes designed to separate opposing streams of traffic in congested or restricted areas to reduce the risk of collision. Governed by Rule 10 of COLREGs.

UKC (Under Keel Clearance): The vertical distance between the lowest point of the ship’s hull and the seabed.
Ullage: The empty space in a tank or cargo hold between the surface of the liquid/cargo and the top of the tank/hold.
UN Number: A four-digit number assigned by the United Nations to identify hazardous substances (dangerous goods).
Uptake (Ballast): The process of taking ballast water into the ship’s tanks.
UTC (Coordinated Universal Time): The primary time standard by which the world regulates clocks and time. It is used for most international reporting and log-keeping in shipping.

VDR / S-VDR (Voyage Data Recorder / Simplified Voyage Data Recorder): The “black box” of a ship, which continuously records vital information such as vessel position, speed, heading, bridge audio, VHF communications, radar data, and alarms. This data is used for accident investigation.
Vetting: A process of inspection and risk assessment of a ship conducted by or on behalf of a commercial entity (e.g., a charterer like an oil major, or an organization like RightShip) to determine its suitability for their use.
VGP (Vessel General Permit): A permit under the US Clean Water Act that regulates incidental discharges from commercial vessels operating in US waters.
VTS (Vessel Traffic Services): Shore-based systems implemented by competent authorities to monitor vessel traffic, provide information, and manage navigation in busy or complex areas.

Waterplane Area: The area of the ship’s hull at the waterline.
WBT (Water Ballast Tank).
WIBON / WCCON / WIFPON / WIPON: Charter party acronyms related to tendering the Notice of Readiness: Whether In Berth Or Not / Whether Customs Cleared Or Not / Whether In Free Pratique Or Not / Whether In Port Or Not. These clauses can allow laytime to commence even if certain conditions (berth availability, customs, health clearance, port entry) have not yet been met.
Windlass: The powerful machine on the forecastle deck used for heaving and paying out the anchor chains.

ZOC (Zone of Confidence): See CATZOC.

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